Folding blade cylinder of a folding machine and method for regulating a folding blade

ABSTRACT

A folding blade cylinder for use in a folding machine includes a cylindrical cradle and a folding blade that can be situated in various positions in the cylindrical cradle. Each position of the folding blade corresponds to a gap in the cylinder cradle surface. These gaps are separated from each other by segments of the cylindrical cradle. In order to move the folding blade from one gap to another, the folding blade is retracted into the interior of the folding blade cylinder.

[0001] The invention relates to a folding blade cylinder of a folding apparatus and to a method for displacing a folding blade on a folding blade cylinder in accordance with the preambles of claims 1 or 15.

[0002] Such cylinders are employed, acting together with a folding jaw cylinder, for making a transverse fold in a sheet of material passing through a gap between the folding blade cylinder and the folding jaw cylinder. To this end, at least one folding blade in the folding blade cylinder can be moved between an inactive position, in which it does not protrude past the exterior surface of the folding blade cylinder, and an active position, so that in the active position it pushes the sheet to be folded into a gap in the oppositely located folding jaw cylinder, which is subsequently closed and conveys the folded sheet clamped in the fold further.

[0003] In order to be able to fold sheets in various formats by means of such a folding blade cylinder, or to form different folds, it is necessary to be able to displace the folding blade on the circumference of the folding blade cylinder between different positions. However, at the same time the exterior surface of the folding blade cylinder should be cylindrically closed as much as possible in order to assure the precise guidance of the sheets of material.

[0004] DE 43 35 048 A1 describes a folding blade cylinder for a folding apparatus with respectively a single gap for the folding blade. The folding blade can be displaced inside this gap in the circumferential direction.

[0005] DE 690 08 007 T2 shows a folding blade cylinder whose folding blade can be moved into a working and a rest position for different types of folds.

[0006] The object of the invention is based on providing a folding blade cylinder of a folding blade cylinder, and a method for displacing a folding blade on a folding blade cylinder.

[0007] In accordance with the invention, this object is attained by means of the characteristics of claims 1 or 15.

[0008] The advantages to be gained by means of the invention lie in particular in that an impediment to the displacement of the blade cylinder by paper dust or similar foreign materials is made impossible, even after a long period of use of the folding blade cylinder with a constant format. Another advantage consists in that tooth impressions in the sheet are prevented.

[0009] To this end it is provided that in place of a single displaceable gap the cradle has a plurality of gaps each assigned to a folding blade, and that the folding blade can be retracted into the interior of the folding blade cylinder sufficiently far so that it can be displaced in the interior of the folding blade cylinder between different positions, each of which is located opposite one of the gaps.

[0010] This can be accomplished for one in that the lift of the folding movement is selected to be so large that in its inactive position the folding blade is located radially inside the interior surface of the cradle, so that it can be freely displaced in this position. Another option is to provide a reduced lift of the folding movement between the extended active and the inactive positions of the folding blade, wherein in the inactive position the folding blade is at least partially located outside of the inner surface of the cradle, and moreover to embody the folding blade so that it can be retracted behind the interior surface of the cradle in order to make possible the displacement of the folding blade to another gap in this way.

[0011] Customarily the movement of such a folding blade is controlled by a lever which runs off on a control cam. In order to be able to retract the folding blade past the inactive position, it is possible to provide an actuator for lifting the lever off this control cam. Such an actuator can be a lift cylinder, for example; electro-magnetically driven actuators can also be considered. A second control cam can also be alternatively provided, which can be displaced against the first mentioned one and has a section which can be brought into contact with the lever arm by this displacement in order to retract the folding blade behind the interior surface of the cradle.

[0012] To prevent the edges of the gap from pressing into the sheet to be folded, the outside located longitudinal edges of the gaps can be beveled.

[0013] Furthermore, a closing body is preferably provided which, coupled with the displacement of the folding blade, can be displaced between one position, in which it does not close a gap occupied by the folding blade, and a position wherein it is retracted into the interior of the folding blade cylinder. Such a closing body can also counteract the formation of an indentation, in particular if it rests flush with the exterior surface of the cradle on a portion of the exterior surface, however, it is more important that it prevents the introduction of a free end of a sheet into the otherwise open gap.

[0014] For easing the displacement of the closing body, and therefore also that of the folding blade, the closing body and/or the gap which can be closed off by it are beveled on their ends facing each other. A spring element can be used for maintaining the closing body in its position by means of a radially outward exerted pressure.

[0015] Exemplary embodiments of the invention are represented in the drawings and will be described in greater detail in what follows.

[0016] Shown are in:

[0017]FIG. 1, a schematic radial section through a folding blade cylinder,

[0018]FIG. 2, an axial section through the folding blade cylinder in FIG. 1,

[0019]FIG. 3, a modification of the folding blade in a radial partial section,

[0020]FIG. 4, a second modification in a radial partial section analogous to the one in FIG. 3,

[0021]FIG. 5, a third modification in a radial partial section analogous to the one in FIG. 3.

[0022] A first embodiment of the folding blade cylinder in an axial and a radial section is represented in FIGS. 1 and 2. The axial section in FIG. 2 shows a shaft 01, to which two flanges 02 have been screwed, fixed against relative rotation. These flanges 02 support the cradle 03 (see FIG. 1) of the folding blade cylinder which, in this embodiment, has been put together from six segments 06, 07, which are respectively separated by gaps 08, or 09, extending radially over the entire distance between the flanges 02.

[0023] Three holding elements 12 equipped with grippers extend through the slits in the segments 06 and are each mounted on spindles 11, which in turn are pivotably suspended between the two flanges 02.

[0024] Two further flanges 13 are arranged, rotatable around the shaft and parallel with the flanges 02. Cross arms 14 extend through elongated holes 16 formed in the shape of a segment of a circle in the flanges 02 and connect the flanges 02 with each other for coupling the rotary movement of the flanges 13. As represented in FIG. 1, in the area between the flanges 02 the cross arms 14 are combined into a hollow cylinder surrounding the shaft 1 in order to achieve the greatest possible torsional rigidity.

[0025] Three spindles 17 of folding blades 18 are rotatably seated on the flanges 13. Each one of the grippers 12 and the folding blades 18 performs a back-and-forth movement in time with the rotation of the folding blade cylinder, which is controlled in a manner known per se by levers 19, or 21, respectively mounted on axial ends of the spindles 11, or 17. These levers 19, 21 support rollers 22 on their ends, which roll off on control cams 23. These control cams 23 have the form of stationary disks, they are not represented in FIG. 2, and in FIG. 1 only in the form of parts of a surface.

[0026] In order to differentiate between the three folding blades 18 represented in FIG. 1, in what follows they will also be called the right, left, or lower folding blades 18. The left and the lower folding blades 18 are in an inactive position in their folding movement, in which they have been retracted as far as to behind the inner surface 24 of the cradle 03. The right folding blade 18 is in an extended, active position, in which its tip slightly protrudes past the surface of the cradle 3 and is therefore capable of pushing a sheet carried along by the gripper 12 into a folding jaw of an oppositely located folding jaw cylinder, not represented.

[0027] In a position slightly displaced against the represented position of the folding blade cylinder, all three folding blades 18 are in the retracted inactive position. In this position it is possible to release a fixed coupling between the flanges 13 and 02 and thus to displace the folding blades 18 in relation to the cradle 03 in a counterclockwise direction in FIG. 1, so that each of the folding blades 18 comes to rest in front of a gap 08, 09. The control cam 23 controlling the folding movement of the folding blades 18 is not rotated along in this case, so that even after the displacement the location at which the folding blades 18 are extended remains at the place where the circumference of the folding blade cylinder touches the (not represented) folding jaw cylinder.

[0028] In the embodiment represented in FIG. 1, the two flanges 13 are connected with each other by L-shaped profiled elements 26 which, on their legs facing the cradle 03, support a closing body 17 which is pressed against the inner surface 24 of the cradle 03 by a spring element 28. In this case the spring element 28 and the closing body 27 are embodied in one piece as a spring plate extending in the axial direction over the entire length of the gaps 09. The closing bodies 27 are arranged in relation to the folding blades in such a way that they close the gaps 09 when the folding blades 18 rest against the gaps 08, as represented in FIG. 1. They prevent a free end of a sheet folded by the folding blades 18 to spring into the gap 09 and to get snagged there. This is particularly useful if the gap 08 corresponds to a delta folding position (corresponds to a second transverse fold), and the gap 09 corresponds to a first transverse folding position.

[0029] When the folding blades 18 rest against the gaps 09, the closing bodies 27 have dipped into the interior of the folding blade cylinder. Such a dipped closing body is represented by a dash-dotted line in FIG. 1 and identified by 28′. On their interior surfaces, the gaps 09 each have beveled flanks 29 which, together with the curved exterior shape of the closing body 27, make it easier for the latter to dip into the interior of the folding blade cylinder in the course of a displacement.

[0030] Similar beveled surfaces 31 are formed on each of the outer edges of the gaps 08, 09 in order to prevent these edges from leaving pressure indentations on the sheets to be processed.

[0031]FIG. 3 shows a partial section through a folding blade cylinder in accordance with a further development. The difference with the embodiment in FIG. 1 lies in that in FIG. 3 the narrow cradle element 07, under which the folding blade can move from the gap 08 to the gap 09 and back, is thinner than the wide segments 06 on each of which the grippers (not represented here) are arranged. FIG. 3 shows the folding blade 18 in its retracted, inactive position. Here, the tip of the folding blade 18 is located radially outward of the inner surfaces 32 of the segments 06, but inside of the inner surfaces 33 of the segments 07. In this way the reduced thickness of the segment 07 permits the reduction of the lift of the folding movement of the folding blade 18, but yet allows it to displace it as needed between the two gaps 08, 09. Along with the reduced lift of the folding movement, the accelerations to which the folding blade, or its spindle 17, are subjected are also reduced. This allows the operation of the folding blade cylinders at a greater rotary speed and/or with reduce wear.

[0032] A second further development is represented in FIG. 4 in a sectional view analogous to the one in FIG. 3. Here, the thickness of the segments 06, 07 is again identical as in the case of FIG. 1; however, the control cam 23 is shaped in such a way that only a lift of the folding movement, which is reduced in comparison with the embodiment in FIG. 1, is achieved. Thus, in the inactive, retracted position of the lifting movement, the tip of the folding blade 18 is located radially between the inner surface 24 and the outer surface of the cradle 03. In order to make possible a displacement of the folding blades 18 between the two gaps 08, 09 in spite of this, linear actuators, in this case hydraulic cylinders 34, are provided in a number corresponding to the number of folding blades 18 and are arranged distributed at the same angular distance. One of these hydraulic cylinders 34 is represented in FIG. 4. It is mounted on the flange 13, which also supports the folding blades 18, so that it always takes up the same position in respect to the folding blade 18 assigned to it, independently of the rotary position of the folding blade cylinder. It has an outwardly oriented piston with a piston rod 36, which is located exactly opposite an end area of the lever 21, or of the roller 22 mounted on the lever 21, mounted for rolling off on the control cam 23. By extending the piston, the roller 22 is lifted off the control cam 23, and the folding blade 18 moves back past the inactive position represented in FIG. 4 into the interior of the folding blade cylinder. As described in respect to FIGS. 1 and 2, the flanges 13, 02 can be rotated in respect to each other in this position in order to displace the folding blades out of their position at the gap 08 into the one at the gap 09, or vice versa.

[0033] It would alternatively also be possible to mount the actuators in a manner fixed in place, in particular on the control cam 23, and to provide the piston rod 36 on its distal end with a cam section facing the roller 22, which is at least sufficiently long for the roller 22 to be able to roll off on it in the course of the displacement of the folding blade 18 from the gap 08 to the gap 09 or vice versa, and in this way to maintain the folding blade 18 at a safe distance from the inner surface 24 during the entire displacement movement. Typically, this distance can be approximately 1.5 mm.

[0034] In accordance with practical points of view, the hydraulic cylinder 34 can also be replaced by other types of linear actuators, for example those with an electromagnetic drive mechanism.

[0035]FIG. 5 shows a sector of a folding blade cylinder in accordance with another variation in a plan view analogous to FIGS. 3 and 4. The structure of the rotating elements of the folding blade cylinder is the same as with the above embodiments and will not be described again. Here, the folding blade 18 is shown in its retracted position in its folding movement, shortly prior to the roller 22 reaching a depression 37 in the control cam 23, which will cause the folding blade 18 to extend into its active position.

[0036] The roller 22 is wider than the control cam 23.

[0037] A second control cam 38 is represented as a dashed outline in FIG. 5. During normal operation of the folding blade cylinder, it is spaced apart from the control cam 23 sufficiently far so that the roller 22 cannot touch it.

[0038] The second control cam 38 has areas 39, 41 of two different radii, wherein the smaller radius of the area 41 is slightly less than the radius of the control cam 34 in its area corresponding to the inactive state of the folding blade 18, while the larger radius of the area 39 is clearly greater than this value.

[0039] To perform the displacement of the folding blades 18, first the second control cam 38 in its orientation represented in FIG. 5 is axially displaced in the direction of the first control cam 23, so that at least a portion of its width comes to lie underneath the roller 22. Thereafter, the second control cam 38 is turned in a clockwise direction. This leads to the roller 22 being supported by the area 39 of larger radius of the second control cam 38, so that the roller 22 is lifted off the first control cam 23 and the folding blade 18 is retracted sufficiently far behind its inactive position represented in FIG. 5 into the interior of the folding blade cylinder so that the tip of the folding blade 18 clearly lies inside the inner surface 24. In this state the displacement of the folding blade 18 can be performed in the same way as in the previously described embodiments. Thereafter the second control cam 38 is again moved away from the first control cam 23, so that the latter can again take up its function of controlling the folding movement.

[0040] The examples shown are based on folding blade cylinders with three folding blades, which can be displaced between respectively two gaps. The invention can also be used in connection with folding blade cylinders with any arbitrary number of folding blades and more than two gaps.

[0041] In the above embodiments, a closing body 27 is only provided for the gaps 09. A corresponding closing body could of course also be arranged on the opposite side of the folding blade 18 in order to close the gap 08 when the folding blade 18 lies at the gap 09.

[0042] The folding blade (18) is displaced from a working position, in which the folding blade (18) is arranged at least at times outside of a cradle (03), into a position of rest, in which the folding blade (18) is arranged inside the cradle (03). In the process, the tip of the folding blade (18) is displaced in a circumferential direction in relation to the cradle (03) inside the cradle (03), i.e. it is moved along underneath segments (07) of the cradle (03).

List of Reference Symbols

[0043]01 Shaft

[0044]02 Flange

[0045]03 Cradle

[0046]04

[0047]05

[0048]06 Segment

[0049]07 Segment

[0050]08 Gap

[0051]09 Gap

[0052]10

[0053]11 Spindle

[0054]12 Gripper

[0055]13 Flange

[0056]14 Cross arm

[0057]15

[0058]16 Elongated hole

[0059]17 Spindle

[0060]18 Folding blade

[0061]19 Lever

[0062]20

[0063]21 Lever

[0064]22 Roller

[0065]23 Control cam

[0066]24 Inner surface

[0067]25

[0068]26 L-shaped profiled element

[0069]27 Closing body

[0070]28 Spring element

[0071]29 Bevel

[0072]30

[0073]31 Bevel

[0074]32 Inner surface

[0075]33 Inner surface

[0076]34 Hydraulic cylinder

[0077]35

[0078]36 Piston rod

[0079]37 Depression

[0080]38 Control cam

[0081]39 Area of 38

[0082]40

[0083]41 Area of 38 

1. A folding blade cylinder of a folding apparatus, having a cylindrical cradle (03) and a folding blade (18), which can be extended from a gap (08, 09) of the cradle (03) and can be displaced in the circumferential direction between different positions on the folding blade cylinder, characterized in that in the circumferential direction the cradle (03) has a plurality of gaps (08, 09) assigned to the folding blade (18), that the folding blade (18) is arranged so it can be selectively displaced so it lies opposite different gaps (08, 09).
 2. The folding blade cylinder in accordance with claim 1, characterized in that the folding blade (18) can be displaced in the interior of the folding blade cylinder between different positions which each are located opposite one of the gaps (08, 09).
 3. The folding blade cylinder in accordance with claim 1, characterized in that the folding blade (18) performs a folding movement between an extended, activated position and an inactive position, wherein in the inactive position the folding blade (18) is located radially inside the inner surface (24, 33) of the cradle (03).
 4. The folding blade cylinder in accordance with claim 3, characterized in that the cradle (03) is constructed of segments (06, 07) of different thicknesses, and that the folding blade (18) can be displaced behind a thinner segment (07).
 5. The folding blade cylinder in accordance with claim 1, characterized in that the folding blade (18) performs a folding movement between an extended, activated position and an inactive position, wherein in the inactive position the folding blade (18) is located at least partially radially outside the inner surface (24) of the cradle (03), wherein the folding blade (18) can be retracted past the inactive position behind the inner surface (24) of the cradle (03).
 6. The folding blade cylinder in accordance with claim 5, characterized in that the folding blade (18) is controlled in its movements by a lever (21) running off on a first control cam (23), and that an actuator is provided for lifting the lever off the first control cam (23).
 7. The folding blade cylinder in accordance with claim 6, characterized in that the actuator is a linear actuator acting on the lever, in particular a work cylinder (34) or an electro-magnetic actuator.
 8. The folding blade cylinder in accordance with claim 6, characterized in that the actuator is a second control cam (36), which can be rotated in respect to the first one.
 9. The folding blade cylinder in accordance with one of the preceding claims, characterized in that the gaps (08, 09) have bevels (31) on their outward located edges.
 10. The folding blade cylinder in accordance with claim 1, characterized in that a closing body (17) closes the respective gap (09) not occupied by the folding blade (18).
 11. The folding blade cylinder in accordance with claim 10, characterized in that the closing body (17) is coupled with the displacement of the folding blade (18) in the circumferential direction.
 12. The folding blade cylinder in accordance with claim 11, characterized in that the gap (09), which can be closed by the closing body (27), and/or the closing body (27), have bevels (29) on their sides facing each other.
 13. The folding blade cylinder in accordance with claim 11 or 12, characterized in that a spring element (28) exerts a radially outward directed force on the closing body (27).
 14. The folding blade cylinder in accordance with claim 13, characterized in that the spring element (28) and the closing body (27) are formed in one piece from a sheet metal strip.
 15. A method for displacing a folding blade (18) on a folding blade cylinder in the circumferential direction, wherein the folding blade (18) is displaced from a working position, in which the folding blade (18) is arranged at least at times outside of a cradle (03), into a position of rest, in which the folding blade (18) is arranged inside the cradle (03), characterized in that the tip of the folding blade (18) is displaced in a circumferential direction in relation to the cradle (03) inside the cradle (03). 